The position of aircraft landing flaps is controlled by landing flap drives in such a way that a variable wing profile curvature is producible. The wing profile is modified by a defined retracting and extending of the landing flap or flaps. Such drives are referred to as "variable camber" landing flap drives.
By using such landing flap drives a gap is formed during normal cruising flight between the wing underside and a leading edge of the landing flap. Such gap should preferably or suitably be covered during normal cruising flight in order to establish advantageous aerodynamic conditions.
The covering of the mentioned gap may be achieved with the aid of a special so-called deflector door referred to herein as wing gap closure flap. Such a wing gap closure flap can on the one hand cover the mentioned gap while on the other hand it can control the air flow during the starting and landing phase. By imposing on the wing gap closure flap a proper position during starting and landing an optimal flow guide may be accomplished between the wing underside and the wing upper side. However, there is room for improvement, especially in the drive for such a wing gap closure flap.